1. Field of the Invention
The invention relates to a housing for an input unit having a rotary switch which is arranged on a printed circuit board, having a setting stem which is assigned to the rotary switch and having a plug socket which is fastened on the printed circuit board, and also having means for fastening the input unit to a wall, with the setting stem reaching through the wall.
2. Description of the Prior Art
Input units of the abovementioned type, which are known per se, are provided with a thread which can be used to fasten it to, for example, a front wall of an appliance housing in such a manner that the setting stem, which is generally assigned an adjusting knob, reaches to the outside through the front wall. In such cases, i.e. in the case of a closed appliance, the inserted input unit is protected by the appliance housing from being accessed and against dirt, and does not require its own housing. An arrangement of the input unit directly on a dividing wall, for example on a dashboard of a motor vehicle, where the access on the rear side must be accessible for monitoring and repairing measures, renders it necessary to assign a protective housing to the input unit. In addition, this application requires the provision of a fastening which is suitable for the surroundings. That is to say, additional measures have to be taken in order to be able to install an input unit, which is ready for operation per se, in the motor vehicle independently of appliances or instrument carriers provided with housings.
The object of the present invention is therefore to house an input unit of the generic type in a manner which is secure against contact and dirt and with the smallest possible outlay on manufacture and installation in such a manner that the setting stem and the plug socket remain accessible, and problem-free installation of the input unit at the installation location and reliable fastening are ensured.
The object is achieved in that the housing has means for supporting the input unit, in that a threaded projection is formed on the housing and in that the fastening of the input unit takes place indirectly by screwing of the housing to the wall.
A preferred embodiment of the housing provides that the housing is designed in two parts in such a manner that one half of the threaded projection is integrally formed on each housing component.
The preferred exemplary embodiment is furthermore distinguished in that means for at least one bayonet-type connection are integrally formed on those walls of the housing components which face away from the threaded-projection halves, and means for at least one latching connection are integrally formed on the walls which are provided with the threaded-projection halves, in that the threaded-projection halves are designed as bearing shells which are assigned to the setting stem, and in that rib elements and slots serving as the mounting for the printed circuit board are provided on the housing components.
With the divided design of the threaded projection, the invention affords the advantage of only having to produce two housing halves which can be joined together without the use of a tool, have relatively rough tolerances and are not connected fixedly to each other until the input unit is fastened to a wall. In this arrangement, the latching connection means are formed on the flange side and the bayonet-type connection means are formed on that side of the housing which is opposite the flange side, which prevents damage-free intervention in the housing when it is fastened to the wall. It should also be mentioned here that instead of the bayonet-type connection means it is also possible to form a film hinge, with the advantage of avoiding any confusion between housing components or any positional corrections during installation of the housing. A further advantage of the design according to the invention can be seen in the fact that the threaded projection of the housing can be produced by injection molding and thus does not cause any additional outlay. Furthermore, the housing according to the invention provides the input unit with sufficient protection against dust, but in particular with secure gripping protection when it is being handled during installation.
It is also advantageous that the input unit is fastened indirectly by fastening of the housing in which it is mounted in an expedient manner. That is to say, a threaded projection can be formed on the housing, this projection providing flange-mounting conditions which are optimum as regards the security of the fastening.